Helicopter gear sleeve part axis pose adjusting method based on eddy current distance measurement

Abstract

The invention discloses a helicopter gear sleeve part assembly pose adjusting method based on eddy current distance measurement. The method comprises the steps of firstly building a gear sleeve part pose measurement system and establishing a measurement coordinate system, then correcting measurement errors of inner arc surface features measured by an eddy current displacement sensor, performing rotary scanning measurement by using the sensor to extract the surface profile of the part, calculating axis inclination angle information of the gear sleeve part in a rough measurement stage, and calculating the axis inclination angle information of the gear sleeve part. Then the relative pose of the sensor and the detected gear sleeve part is adjusted; and in the accurate measurement stage, coordinates of the section contour circle centers of the upper and lower inner arc surfaces are obtained, axis pose parameters of the gear sleeve part are obtained through calculation, and finally the assembly pose is adjusted. The method aims to correct the eddy current measurement error of the inner arc surface characteristic on the premise of no target, no contact and no grease interference, improves the measurement precision and efficiency of the assembly pose of the gear sleeve part, and can be used for high-precision measurement and adjustment of the axis pose of the part in the automatic assembly process of the gear sleeve part.

Description

Technical Field

[0001] The invention relates to a method for adjusting the position and posture of an axis of a gear sleeve part, and relates to the technical field of assembly measurement of gear sleeve parts, and in particular to a method for adjusting the position and posture of an axis of a helicopter gear sleeve part based on eddy current ranging. Background Art

[0002] The assembly of the helicopter lift system mainly involves the docking assembly of the main reducer, automatic tilt device and main rotor hub. The middle section of the main rotor hub inner cavity and the main reducer shaft rely on involute spline meshing connection, and the matching accuracy is high. The current assembly mode is that workers lift the main rotor hub by a crane, and push it to dock with the main reducer shaft after repeated observation. The process of lifting and placing is difficult to accurately control the movement of components, which is easy to damage parts and has low assembly efficiency.

[0003] In recent years, with the rapid development of aircraft automated assembly related technologies, domestic and foreign researchers have developed advanced attitude adjustment and positioning mechanisms to meet the modern production requirements of the aerospace field. However, in the process of automated docking and assembly of the lift system, simply clamping with a fixture or positioning with a tool cannot guarantee the attitude accuracy requirements during assembly of the main propeller hub. It is often necessary to obtain the attitude information of the parts to be assembled through high-precision measurement methods to guide the attitude adjustment mechanism to adjust the attitude.

[0004] At present, relevant domestic research has met the requirements of posture measurement in the process of aircraft automated assembly to a certain extent. For example, the paper "Research Progress of High-Precision Measurement Technology in Large Aircraft Assembly" mentioned a high-precision measurement method for large-space measurement fields in aircraft assembly. Its measurement principle is to measure the target installed on the target part through advanced digital measurement equipment such as laser trackers and iGPS (indoor GPS), obtain the spatial position information of multiple points in the aircraft design coordinate system, and then solve the spatial posture information of the aircraft assembly. This method requires the installation of measurement targets at appropriate positions on the surface of the parts, and the need to keep the optical path between the measurement equipment and the target unobstructed. Due to the lack of external reference reference and the existence of occlusion on the main rotor hub, this type of measurement method using targets is not applicable. For example, the patent application with publication number CN112815850A and titled "A Method and Device for Measuring the Posture of a Cylinder" discloses a method and device for measuring the posture of a cylinder. In this method, three linear laser displacement sensors are arranged around the cylinder to be measured and their values ​​are moved to obtain the relevant parameters of the measurement interface of the cylinder to be measured at different heights, and the posture inclination of the cylinder is calculated. In this method, the measurement of the outer cylindrical surface is not limited by the size of the sensor. Although the product rotation is avoided, the large number of sensors required increases the cost, and the laser cannot guarantee accurate measurement when the measured surface is contaminated or blocked. For the internal parts of the gear sleeve of the lift system, grease is often applied to the mating surface before assembly. Non-contact optical sensors such as laser and vision will be disturbed and cause reading errors, making it difficult to meet the measurement accuracy requirements. In addition, the internal arc surface and tooth profile space of the parts are small, and there are also high requirements for the sensor size and measurement device.

[0005] Eddy current displacement sensors have the characteristics of micron-level measurement accuracy, measurement accuracy is not affected by grease on the measured surface, and non-contact measurement. However, eddy current displacement sensors are generally used for measuring flat or nearly flat metal conductors, and can usually maintain good measurement accuracy. The feature to be measured of the gear sleeve part in the lift system is an inner arc surface with a large curvature. At the same time, the initial posture of the part is tilted, which causes the axis of the probe to be offset relative to the normal vector of the measured point of the inner arc surface contour when the eddy current sensor is extended into the interior of the part for rotational scanning. The above factors will restrict the accuracy of eddy current measurement to varying degrees. In order to ensure that the inner arc surface features inside the main hub can be measured accurately and reliably, it becomes particularly important to accurately extract the contour information after compensating for the sensor measurement error and quickly solve the assembly posture of the part. Summary of the invention

[0006] In order to solve the problems existing in the background technology, the present invention provides a method for adjusting the axis position of a helicopter gear sleeve part based on eddy current ranging. The technical problem to be solved by the present invention is to correct the measurement error when the eddy current displacement sensor probe is offset relative to the inner arc surface feature, accurately extract the characteristic contour of the inner arc surface covered by grease, and solve the axis position of the gear sleeve part. The method of the present invention can ensure the measurement accuracy while improving the measurement efficiency.

[0007] The technical solution adopted by the present invention is:

[0008] The method for adjusting the assembly posture of a helicopter gear sleeve part based on eddy current ranging of the present invention comprises:

[0009] Step 1) Build a gear sleeve part posture measurement system including an eddy current displacement sensor and establish a measurement coordinate system.

[0010] Step 2) In the measurement coordinate system, when the eddy current displacement sensor of the gear sleeve part posture measurement system performs measurement error measurement on the inner arc surface feature of the gear sleeve part of the helicopter, an eddy current correction model is established.

[0011] Step 3) Use the eddy current displacement sensor of the gear sleeve part posture measurement system to perform rotational scanning measurement on the measured point on the gear sleeve part, and then obtain the measured distance and offset of the measured point, and input the measured distance and offset of the measured point into the eddy current correction model for processing to obtain the actual lift-off distance of the measured point, and determine the coordinates of the measured point in the measurement coordinate system according to the rotation radius of the eddy current displacement sensor, the equally spaced angles between each measured point on the gear sleeve part, and the actual lift-off distance of the measured point.

[0012] Step 4) Use an eddy current displacement sensor to perform a rough measurement on the gear sleeve part, obtain the axis inclination angle information of the gear sleeve part according to the coordinates of the measured point in the measurement coordinate system, and then obtain the posture information of the gear sleeve part in the rough measurement stage.

[0013] Step 5) Based on the posture information of the gear sleeve part in the rough measurement stage and the target assembly posture, use the posture adjustment device to roughly adjust the relative posture between the rotation axis of the eddy current displacement sensor and the axis of the gear sleeve part, so that the posture of the gear sleeve part is adjusted to be close to the target assembly posture.

[0014] Step 6) Use an eddy current displacement sensor to accurately measure the roughly adjusted gear sleeve part, so as to obtain the center coordinates of the elliptical cross-section contours of the two inner arc surfaces of the gear sleeve part in the measurement coordinate system.

[0015] Step 7) The spatial position of the axis of the gear sleeve part is calculated according to the center coordinates of the elliptical cross-section contour of the two inner arc surfaces of the gear sleeve part, and finally the spatial position of the axis of the gear sleeve part is adjusted to the target assembly position to complete the assembly position adjustment of the gear sleeve part.

[0016] In the step 1), the gear sleeve part posture measurement system also includes a motion control mechanism and a cantilever tooling, the motion control mechanism has at least 4 degrees of freedom, including 3 translational degrees of freedom in the spatial rectangular coordinate direction and a rotational degree of freedom around the vertical direction, the end flange of the motion control mechanism is connected to the cantilever tooling, and a positioning pin hole is provided on the end flange; the cantilever tooling includes a crossbeam and a longitudinal beam, the end flange of the motion control mechanism is connected to the upper surface of one end of the crossbeam, the radial direction of the end flange is parallel to the length direction of the crossbeam, the lower surface of the crossbeam is provided with a slide groove along its own length direction, the top end of the longitudinal beam is slidably installed in the slide groove of the crossbeam, and the longitudinal beam moves along the slide groove Move to adjust the cantilever length between the longitudinal beam and the end flange; the longitudinal beam is provided with reinforcing ribs to prevent bending deformation, and the bottom end of the longitudinal beam is provided with a through hole for installing the eddy current displacement sensor. The eddy current displacement sensor includes a sensor probe, a sensor connecting cable and a sensor fixing nut. The sensor probe is installed in the through hole of the longitudinal beam through the sensor fixing nut. The sensor probe is connected to an external sensor processing device through the sensor connecting cable. The orientation of the sensor probe is parallel to the length direction of the crossbeam; the straight-line distance between the central symmetrical point of the locating pin hole on the end flange and the head of the sensor probe is used as the rotation radius r of the eddy current displacement sensor.

[0017] The measurement coordinate system of the gear sleeve part posture measurement system takes the center of the bottom surface of the base of the motion control mechanism as the origin O, the measurement direction of the eddy current displacement sensor along its axis after installation as the X-axis, and the vertical upward direction as the Z-axis to establish a right-handed rectangular coordinate system O-XYZ.

[0018] The step 2) is as follows:

[0019] Step 2.1) The eddy current displacement sensor is driven to move into the gear sleeve part by a motion control mechanism, and a number of measured points are provided at equally spaced angles on the inner surface of the gear sleeve part; the sensor probe of the eddy current displacement sensor is centered, and the sensor probe is driven to move in steps along the X-axis and Y-axis of the measurement coordinate system in the gear sleeve part by the motion control mechanism to determine the range of the eddy current displacement sensor, so that the eddy current displacement sensor is within the range when moving, and at the same time, the axis of the sensor probe is coincident with the normal vector of the currently measured measured point.

[0020] Step 2.2) Use an eddy current displacement sensor to measure the inner arc surface features of the gear sleeve part, change the lift-off distance h and offset δ of the sensor probe relative to the measured point in plane XOY, the lift-off distance is the actual distance of the sensor probe surface relative to the measured point, at this time due to the influence of the curved surface and the offset, the measurement distance H of the sensor probe is not equal to the actual lift-off distance, calibrate the N offsets of the same inner arc surface feature at M lift-off distances, and obtain M×N sensor probe measurement distances H(m,n) and sensor lift-off distances h(m,n), where m=1, 2,…,M, n=1, 2,…,N.

[0021] Step 2.3) For each offset, all M lift-off distances h and measured distances H under the current offset are fitted with a second-order polynomial, thereby obtaining a second-order polynomial fitting result of the offset. The second-order polynomial fitting result of the offset is h(m, n) = A ε (n)·H(m,n) 2 +B ε (n)·H(m,n)+C ε (n), obtain the first polynomial parameter A of the nth offset according to the second-order polynomial fitting result ε (n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n).

[0022] Step 2.4) For each offset, the first polynomial parameter A of the current offset is ε (n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n) Perform a second-order polynomial fit to obtain the first polynomial parameter A ε (n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n) The second-order polynomial fitting result, the first polynomial parameter A ε The second-order polynomial fitting result of (n) is A ε ′(n), A ε ′(n)=A ε0 ·T(n) 2 +A ε1 ·T(n)+A ε2 , the second polynomial parameter B ε The second-order polynomial fitting result of (n) is B ε ′(n), B ε ′(n)=B ε0 ·T(n) 2 +B ε1 ·T(n)+B ε2 , the third polynomial parameter Cε The second-order polynomial fitting result C of (n) ε ′(n), C ε ′(n)=C ε0 ·T(n) 2 +C ε1 ·T(n)+C ε2 , thereby obtaining the first intermediate correction parameter A ε0 , the second intermediate correction parameter A ε1 , the third intermediate correction parameter A ε2 , the fourth intermediate correction parameter B ε0 , the fifth intermediate correction parameter B ε1 , the sixth intermediate correction parameter B ε2 , the seventh intermediate correction parameter C ε0 , the eighth intermediate correction parameter C ε1 and the ninth intermediate correction parameter C ε2 , where T(n) is the offset distance of the nth offset.

[0023] Step 2.5) When the eddy current displacement sensor is used to perform rotational scanning measurement on the inner arc surface features of the gear sleeve part, the measurement distance H of the sensor probe is obtained. At the same time, according to the offset δ of the sensor probe relative to the measured point in the plane XOY and the nine intermediate correction parameters δ in step 2.4), an eddy current correction model is established. According to the eddy current correction model, the actual lift-off distance h after eddy current correction can be obtained.

[0024] In the step 2.5), the eddy current correction model is as follows:

[0025] h=A ε ′(n)·H 2 +B ε ′(n)·H+C ε ′(n)

[0026] A ε ′(n)=A ε0 ·δ 2 +A ε1 ·δ+A ε2

[0027] B ε ′(n)=B ε0 ·δ 2 +B ε1 ·δ+B ε2

[0028] C ε ′(n)=C ε0 ·δ 2 +C ε1 ·δ+C ε2

[0029] Wherein, h is the actual lift-off distance of the sensor probe relative to the measured point in plane XOY.

[0030] The step 3) is specifically as follows: in the measurement of the axis position of the gear sleeve part, the motion control mechanism drives the sensor probe to perform a rotation scan, and the measurement data of the sensor probe is synchronously obtained, including the measurement distance H of the sensor probe and the offset δ relative to the measured point in the plane XOY, and the measurement data of the sensor probe is input into the eddy current correction model for processing. After the eddy current correction model is processed, the real lift-off distance h of the sensor probe relative to the measured point in the plane XOY is output; according to the real lift-off distance h of the sensor probe relative to the measured point in the plane XOY, the rotation radius r of the sensor probe and the equally spaced angle θ between each measured point, the coordinates of the measured point in the measurement coordinate system are determined, as follows:

[0031]

[0032] Among them, x i and i are respectively the X-axis and Y-axis coordinates of the ith measured point in the measuring coordinate system, i=1, 2, ..., I, I is the total number of measured points on the cross section of the inner arc surface of the gear sleeve part in the measuring coordinate system, 1=360 / θ.

[0033] The measured point refers to the three-dimensional coordinates (x i ,y i , z i ), where i is the number of the discrete point; z i The coordinates are determined by the end flange position of the motion control mechanism and the geometric dimensions of the cantilever fixture in the Z-axis direction. The end flange position changes with the movement of the motion control mechanism and can be read directly. The geometric dimensions are fixed lengths and are obtained through measurement.

[0034] The step 4) is as follows:

[0035] Step 4.1) During the rough measurement stage of the gear sleeve part, the sensor probe rotates one circle around the rotation axis of the gear sleeve part. The rotation section of the gear sleeve part is parallel to the measurement coordinate system XOY. Generally, the gear sleeve part is in an inclined state, and the rotation section of the gear sleeve part intersects with the inner cylindrical surface of the gear sleeve part to form an elliptical contour.

[0036] Perform ellipse fitting on a measured point on the cross section of the ellipse profile to obtain the coefficients of the ellipse profile (A γ , B γ , C γ , Dγ , E γ , F γ ), thereby determining the ellipse; in addition to the algebraic equation, the ellipse can also be expressed by the coordinates of the center (x ci ,y Ci ), the major semi-axis r of the ellipse a , short semi-axis r b The five geometric parameters, , the angle β between the major axis and the X-axis, are uniquely determined.

[0037] Specifically, the coefficients of the algebraic equation of the ellipse (A) can be obtained by minimizing the following objective function J by using the direct least squares method to fit the ellipse algebraically. γ , B γ , C γ , D γ , E γ , F γ ):

[0038]

[0039] Among them, A γ , B γ , C γ , D γ 、E γ and F γ are the first, second, third, fourth, and fifth coefficients of the algebraic equation of the ellipse.

[0040] Step 4.2) Obtain the angle between the section where the contour ellipse of the gear sleeve part is located and the perfect circular section passing through the center of the ellipse contour according to the curvature radius R of the inner arc surface of the gear sleeve part and the geometric parameters of the ellipse contour. Thereby, the axis inclination angle information of the gear sleeve part is obtained. At this time, only the inclination degree of the gear sleeve part can be obtained, but it cannot be adjusted.

[0041] Step 4.3) Based on the axis inclination angle information of the gear sleeve part and the minor axis direction vector of the elliptical contour Determine the direction vector of the axis direction of the gear sleeve part and the coordinates C of the center of the ellipse contour on the axis c =(x Ci ,y Ci , z Ci ), s1, s2 and s3 are the projections of the axial direction of the gear sleeve parts on the X, Y and Z axis directions of the measurement coordinate system. Ci ,y Ci and z Ci are the center C of the ellipse contour cIn the X, Y and Z axis coordinates of the measurement coordinate system, the rotation axis of the eddy current displacement sensor is parallel to the Z axis of the measurement coordinate system, and the unit vector of the rotation axis of the eddy current displacement sensor is The minor axis direction vector of the ellipse outline The geometric parameters of the ellipse are used to obtain the position and posture information of the axis of the gear sleeve part during the roughing stage.

[0042] The step 6) is specifically to use the sensor probe of the eddy current displacement sensor to move along the vertical rotation axis, select the elliptical cross-sectional profiles whose inner arc surfaces at the upper and lower positions of the gear sleeve part are parallel to the plane XOY, perform elliptical least squares fitting on each elliptical cross-sectional profile, obtain the center position of each elliptical cross-sectional profile, add the Z coordinate of the cross section where the center of each elliptical cross-sectional profile is located, and obtain the spatial coordinates C1=(x 11 ,y 11 , z 11 ) and C2=(x 22 ,y 22 , z 22 ), where x 11 ,y 11 and z 11 are the X, Y, and Z axis coordinates of the center of the first elliptical cross-section profile in the measurement coordinate system, respectively. 22 ,y 22 and z 22 are the X, Y and Z axis coordinates of the center of the second elliptical cross-section contour in the measurement coordinate system. According to the theory of spatial geometry, the straight line L formed by connecting the spatial coordinates of the centers of the two elliptical cross-section contours is C Theoretically, it should coincide with the axis of the gear sleeve parts.

[0043] The step 7) is specifically that the axis of the gear sleeve part belongs to a spatial straight line, and the direction is the same as the direction vector Similarly, according to the center coordinates of the elliptical cross-section contours of the two inner arc surfaces of the gear sleeve part, the spatial equation of the axis of the gear sleeve part is determined as follows:

[0044]

[0045] p=s1 / s3

[0046] q=s2 / s3

[0047] Among them, x, y and z are the X, Y and Z axis coordinates of a point on the axis of the gear sleeve part in the measurement coordinate system; p and q are the first and second direction vector parameters; x0 and y0 are the X and Y axis coordinates of the intersection point C0 of the axis of the gear sleeve part and the XOY plane of the measurement coordinate system, z0 = 0; s1, s2 and s3 are the direction vectors of the axis direction of the gear sleeve part Projection in the X, Y and Z directions of the measurement coordinate system.

[0048] For the axis measurement requirements of the inner cylindrical surface features, it is necessary to determine the direction of the axis. The movement of the cylinder up and down along the axis and the rotation around its own axis will not affect the measurement result of the axis. Therefore, the axis equation is simplified and the point through which the axis passes is set on the XOY plane of the measurement coordinate system, that is, z0=0. Assuming p=s1 / s3 and q=s2 / s3, a simplified expression of the axis space equation can be obtained.

[0049] The coordinates of the center of the elliptical cross-section contour of the two inner arc surfaces of the gear sleeve part are input into the spatial equation of the gear sleeve part for processing to obtain the coordinates of the intersection point C0 of the axis of the gear sleeve part and the XOY plane of the measurement coordinate system and the direction vector of the axis direction of the gear sleeve part. The details are as follows:

[0050]

[0051] Among them, x 11 ,y 11 and z 11 are the X, Y and Z axis coordinates of the center C1 of the first elliptical cross-section profile in the measurement coordinate system, respectively. 22 ,y 22 and z 22 They are respectively the X, Y and Z axis coordinates of the center C2 of the second elliptical cross-section profile in the measurement coordinate system.

[0052] The coordinates of the intersection point C0 of the axis of the gear sleeve part and the XOY plane of the measurement coordinate system and the direction vector of the axis direction of the gear sleeve part As the posture parameter of the axis of the gear sleeve part, the spatial posture of the axis of the gear sleeve part is further determined.

[0053] The electronic device of the present invention comprises: a memory and a processor coupled to each other, wherein the memory stores program data, and the processor calls the program data to execute the method as described above.

[0054] The computer-readable storage medium of the present invention stores program data thereon, and when the program data is executed by a processor, the method described above is implemented.

[0055] The beneficial effects of the present invention are:

[0056] 1. The present invention uses an eddy current displacement sensor to perform a rotational scan on the inner arc surface features inside the gear sleeve part around the rotation axis to obtain point cloud information on the surface of the gear sleeve part. In the rough measurement stage, the elliptical contour is obtained by intersecting the sensor's rotating section with the measured part. After the initial solution of the part's inclination angle and the rough measurement axis position information is adjusted, the fine measurement stage is entered to obtain the elliptical contour of the intersection of two parallel sections with the measured part, and the axis position information is obtained by calculating the center coordinates, avoiding the low accuracy of a single measurement and the low efficiency of repeated measurements.

[0057] 2. The present invention uses an eddy current displacement sensor to assist a motion control mechanism in performing rotational scanning on parts, and processes the point cloud data obtained by the scanning to resolve the axis position and posture of the parts. The present invention can be used to measure the spatial posture of metal parts with inner arc surface features of any size. Compared with the existing measurement method that requires the installation and pasting of targets, the measurement process does not contact the measured parts, thereby avoiding damage to the surface of the parts. At the same time, for products measured in large quantities, the target installation or pasting process is eliminated, thereby improving the measurement efficiency. Compared with the measurement method of extracting contours with laser sensors or taking photos with industrial cameras, eddy current sensors are not affected by grease on the measured surface.

[0058] In summary, the method of the present invention aims to correct the eddy current measurement error of the inner arc surface features under the premise of no target, no contact and no interference from grease, improve the measurement accuracy and efficiency of the assembly posture of the gear sleeve parts, and can be used for high-precision measurement and adjustment of the axis posture of the parts during the automated assembly of the gear sleeve parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of the gear sleeve parts position and posture measurement system of the present invention;

[0060] Figure 2 It is a schematic diagram of the installation of the end flange and the cantilever tooling of the motion control mechanism of the present invention;

[0061] Figure 3 It is a flowchart of the implementation of the axis position and posture measurement method of the present invention;

[0062] Figure 4 It is a schematic diagram of the inner arc surface feature calibration of the present invention;

[0063] Figure 5 It is a schematic diagram of the coincidence of the sensor axis and the normal vector of the measured point after the centering process of the present invention;

[0064] Figure 6 This is a schematic diagram of the measurement error of the inner arc surface of the eddy current before correction by the present invention;

[0065] Figure 7 It is a schematic diagram of the output characteristics of the sensor after the eddy current measurement error is corrected in the present invention;

[0066] Figure 8 It is a schematic diagram of the principle of the axis rough measurement stage of the present invention;

[0067] Fig. 9 It is a schematic diagram of the principle of the axis precision measurement stage of the present invention;

[0068] In the figure: 1. motion control mechanism, 2. cantilever tooling, 21. crossbeam, 22. longitudinal beam, 3. eddy current displacement sensor, 4. gear sleeve parts. DETAILED DESCRIPTION

[0069] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0070] like Figure 1 and Figure 2 As shown, the gear sleeve part posture measurement system constructed by the present invention includes a motion control mechanism 1, a cantilever tool 2 and an eddy current displacement sensor 3. The motion control mechanism 1 has at least 4 degrees of freedom, including 3 translational degrees of freedom in the spatial rectangular coordinate direction and a rotational degree of freedom around the vertical direction. The end flange of the motion control mechanism 1 is connected to the cantilever tool 2, and a positioning pin hole is provided on the end flange; the cantilever tool 2 includes a crossbeam 21 and a longitudinal beam 22. The end flange of the motion control mechanism 1 is connected to the upper surface of one end of the crossbeam 21, and the radial direction of the end flange is parallel to the length direction of the crossbeam 21. The lower surface of the crossbeam 21 is provided with a slide groove along its own length direction. The top end of the longitudinal beam 22 is slidably installed in the slide groove of the crossbeam 21, and the longitudinal beam 22 moves along the slide groove Move to adjust the cantilever length between the longitudinal beam 22 and the end flange; the longitudinal beam 22 is provided with a reinforcing rib to prevent bending deformation, and the bottom end of the longitudinal beam 22 is provided with a through hole for installing the eddy current displacement sensor 3, the eddy current displacement sensor 3 includes a sensor probe 31, a sensor connecting cable 32 and a sensor fixing nut 33, the sensor probe 31 is installed in the through hole of the longitudinal beam 22 through the sensor fixing nut 33, the sensor probe 31 is connected to the external sensor processing device through the sensor connecting cable 32, and the orientation of the sensor probe 31 is parallel to the length direction of the crossbeam 21; the straight line distance between the central symmetric point of the locating pin hole on the end flange and the head of the sensor probe 31 is used as the gyration radius r of the eddy current displacement sensor 3. The internal size and shape of the gear sleeve part 4 are exactly the same as the internal features of the main hub, with the upper and lower parts being inner arc surface features and the middle being a toothed spline profile feature. Preferably, the motion control mechanism 1 adopts an industrial robot with six degrees of freedom in space and high motion accuracy.

[0071] The working principle of the present invention is as follows:

[0072] The end flange of the motion control mechanism 1 of the present invention is fixedly connected to the cantilever tooling 2, and is positioned by pin holes to ensure that the movable direction of the longitudinal beam 22 is in line with the X-axis motion direction of the motion control mechanism 1. The eddy current displacement sensor 3 is installed on the longitudinal beam 22, which can ensure that the axis of the eddy current displacement sensor 3 passes through the rotation axis of the end flange of the motion control mechanism 1. When it is in the initial position, the measurement direction of the eddy current displacement sensor 3 is the same as the X-axis direction of the motion control mechanism 1. Since the eddy current displacement sensor 3 measures the area covered by the sensor probe 31, when the inner arc surface feature of the inclined gear sleeve part 4 is rotated, the sensor probe 31 cannot be guaranteed to be facing the measured area, and there is an offset between its axis and the normal vector direction of the measured point, which introduces a measurement error, so calibration is required. The eddy current displacement sensor 3 is controlled to obtain measurement values ​​at different offset amounts along the offset direction, and the eddy current displacement sensor 3 is controlled to move along the lift-off direction to obtain measurement values ​​at different lift-off distances. The actual distance between the surface of the sensor probe 31 of the eddy current displacement sensor 3 and the surface of the measured gear sleeve part 4 is the true value. The output voltage of the eddy current displacement sensor 3 can be converted according to the sensor sensitivity coefficient to obtain the measurement value of the distance. Therefore, a relationship curve between the true value and the measured value can be established to correct the measurement error.

[0073] When measuring the axis position of the gear sleeve part 4 with unknown posture, the end movement of the motion control mechanism 1 is controlled, and the eddy current displacement sensor 3 is driven by the cantilever tooling 2 to penetrate into the gear sleeve part 4, and the upper inner arc surface feature is aligned for rotation scanning to obtain the cross-sectional contour. According to the spatial geometry, the contour is an ellipse. The elliptical curve equation is obtained by fitting the ellipse, and the elliptical geometric parameters are further converted to obtain the axis position of the gear sleeve part 4. The position of the gear sleeve part 4 is adjusted so that its axis coincides with the rotation axis of the eddy current displacement sensor 3. At this time, the upper and lower inner arc surface features are precisely measured, and the ellipse is also fitted to obtain the coordinates of the ellipse center of the two cross sections, and finally the axis position of the gear sleeve part 4 is obtained.

[0074] The specific embodiments of the present invention are as follows:

[0075] like Figure 3 As shown in FIG. 1 , the implementation process of the helicopter gear sleeve part axis position adjustment method based on eddy current ranging proposed by the present invention comprises the following steps:

[0076] Step 1: Establish a measurement coordinate system.

[0077] The measurement coordinate system of the gear sleeve part posture measurement system takes the center of the base bottom surface of the motion control mechanism 1 as the origin O, the measurement direction of the eddy current displacement sensor 3 along its axis after installation as the X-axis, and the vertical upward direction as the Z-axis to establish a right-handed rectangular coordinate system O-XYZ.

[0078] Step 2: The eddy current displacement sensor 3 measures the inner arc surface characteristics and corrects the measurement error.

[0079] In the measurement coordinate system, when the eddy current displacement sensor 3 of the gear sleeve part posture measurement system measures the inner arc surface characteristics of the helicopter gear sleeve part 4, measurement error correction is performed, and then an eddy current correction model is established.

[0080] 1) The eddy current displacement sensor 3 is driven to move into the gear sleeve part 4 by the motion control mechanism 1, and a number of measured points are provided at equal intervals in the inner surface of the gear sleeve part 4; the sensor probe 31 of the eddy current displacement sensor 3 is centered, and the sensor probe 31 is driven to move stepwise along the X-axis and Y-axis of the measurement coordinate system in the gear sleeve part 4 by the motion control mechanism 1, first along the X-axis so that the measured value is in the middle range of the measuring range, and then along the Y-axis, the measured value corresponding to the current position is read statically after each 1 mm movement, and compared with the measured values ​​of the two positions before and after, respectively, until the measured value of the current position is greater than the measured value of the positions on both sides, the step length is halved and then moved again within the range between the positions on both sides, until it moves with the minimum movement resolution of the motion control mechanism 1, and it is determined that the sensor probe 31 remains at the position where the measured value of the sensor probe 31 is the largest, so that the eddy current displacement sensor 3 is located within the measuring range when moving, and at this time, the axis of the sensor probe 31 coincides with the normal vector of the measured point currently being measured, such as Figure 5 shown.

[0081] 2) An eddy current displacement sensor 3 is used to measure the inner arc surface features of the gear sleeve part 4. The motion control mechanism 1 drives the sensor probe 31 to move along the lifting direction and the offset direction, and changes the lifting distance h and the offset δ of the sensor probe 31 relative to the measured point in the plane XOY. The lifting distance is the actual distance between the surface of the sensor probe 31 and the measured point. At this time, due to the influence of the curved surface and the offset, the measured distance H of the sensor probe 31 is not equal to the actual lifting distance. The N offsets of the same inner arc surface feature at M lifting distances are calibrated to obtain M×N measurement distances H(m, n) and sensor lifting distances h(m, n) of the sensor probe 31, where m=1, 2, ..., M, and n=1, 2, ..., N.

[0082] 3) For each offset, all M lift-off distances h and measured distances H under the current offset are fitted with a second-order polynomial, thereby obtaining a second-order polynomial fitting result of the offset. The second-order polynomial fitting result of the offset is h(m, n) = A ε (n)·H(m,n) 2 +B ε (n)·H(m,n)+C ε (n), obtain the first polynomial parameter A of the nth offset according to the second-order polynomial fitting result ε(n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n).

[0083] 4) For each offset, the first polynomial parameter A of the current offset ε (n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n) Perform a second-order polynomial fit to obtain the first polynomial parameter A ε (n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n) The second-order polynomial fitting result, the first polynomial parameter A ε The second-order polynomial fitting result of (n) is A ε ′(n), A ε ′(n)=A ε0 ·T(n) 2 +A ε1 ·T(n)+A ε2 , the second polynomial parameter B ε The second-order polynomial fitting result of (n) is B ε ′(n), B ε ′(n)=B ε0 ·T(n) 2 +B ε1 ·T(n)+B ε2 , the third polynomial parameter C ε The second-order polynomial fitting result C of (n) ε ′(n), C ε ′(n)=C ε0 ·T(n) 2 +C ε1 ·T(n)+C ε2 , thereby obtaining the first intermediate correction parameter A ε0 , the second intermediate correction parameter A ε1 , the third intermediate correction parameter A ε2 , the fourth intermediate correction parameter B ε0 , the fifth intermediate correction parameter B ε1 , the sixth intermediate correction parameter B ε2 , the seventh intermediate correction parameter C ε0 , the eighth intermediate correction parameter C ε1 and the ninth intermediate correction parameter C ε2 , where T(n) is the offset distance of the nth offset.

[0084] 5) When the eddy current displacement sensor 3 is used to perform a rotary scanning measurement on the inner arc surface feature of the gear sleeve part 4, the measurement distance H of the sensor probe 31 is obtained. At the same time, according to the offset δ of the sensor probe 31 relative to the measured point in the plane XOY and the nine intermediate correction parameters δ in step 2.4), an eddy current correction model is established. According to the eddy current correction model, the actual lift-off distance h after eddy current correction can be obtained. The eddy current correction model is specifically as follows:

[0085] h=A ε ′(n)·H 2 +B ε ′(n)·H+C ε ′(n)

[0086] A ε ′(n)=A ε0 ·δ 2 +A ε1 ·δ+A ε2

[0087] B ε ′(n)=B ε0 ·δ 2 +B ε1 ·δ+B ε2

[0088] C ε ′(n)=C ε0 ·δ 2 +C ε1 ·δ+C ε2

[0089] Wherein, h is the actual lifting distance of the sensor probe 31 relative to the measured point in the plane XOY.

[0090] The actual distance h after eddy current correction can be obtained later according to the eddy current correction model. The above method is used to correct the inner arc surface with a curvature radius of 90.5 mm. The process is as follows: Figure 4 As shown, the lift-off distance h is set to change in the range of 2-7 mm and moves in 0.5 mm steps, with a total of 11 lift-off distances; the offset δ varies in the range of 0-9 mm, with a change interval of 1 mm, with a total of 10 offsets. The diameter of the sensor probe 31 is 16 mm.

[0091] During the calibration process, the lift-off distance h changes within the range of 2-7 mm, and the offset δ changes within the range of 0-9 mm, such as Figure 6 As shown in FIG. 1 , the measurement error when the sensor probe 31 measures the inner arc surface without correction is affected by the curvature of the inner arc and the offset of the sensor probe 31. The maximum measurement error without correction is -1.44 mm. Figure 7As shown, this is the lift-off distance-measurement distance output characteristic curve of the eddy current displacement sensor after correction. The measurement error range of the sensor probe 31 after correction is within ±0.017mm. It can be seen that the eddy current measurement error of the large curvature inner arc surface after correction is significantly reduced, meeting the accuracy requirement for contour extraction of the gear sleeve part 4.

[0092] Step 3: The eddy current displacement sensor 3 performs rotational scanning measurement.

[0093] In the embodiment of measuring the axis position of the gear sleeve part 4, the end flange of the motion control mechanism 1 rotates, and the sensor probe 31 is connected to the flange through the cantilever fixture 2. A rotation command can be sent to the motion control mechanism 1 to drive the sensor probe 31 to rotate, and a refresh and measurement command can be sent to the sensor probe 31 simultaneously to obtain the measurement data of the sensor probe 31 in real time. In addition, the rotation radius r of the sensor probe 31 and the equally spaced angle θ between the measured points, as well as the actual measurement distance h of the sensor probe 31 after correction, can also be input.

[0094] Firstly, the eddy current displacement sensor 3 of the gear sleeve part posture measurement system is used to perform a rotation scanning measurement on the measured point on the gear sleeve part 4, and then the measurement distance and offset of the measured point are obtained. The measured distance and offset of the measured point are input into the eddy current correction model for processing to obtain the actual lift-off distance of the measured point. The coordinates of the measured point in the measurement coordinate system are determined according to the rotation radius of the eddy current displacement sensor 3, the equally spaced angles between the measured points on the gear sleeve part 4 and the actual lift-off distance of the measured point.

[0095] In the measurement of the axis position and posture of the gear sleeve part 4, the motion control mechanism 1 drives the sensor probe 31 to perform a rotational scan, and synchronously obtains the measurement data of the sensor probe 31, including the measurement distance H of the sensor probe 31 and the offset δ relative to the measured point in the plane XOY, and the measurement data of the sensor probe 31 is input into the eddy current correction model for processing. After the eddy current correction model is processed, the real lifting distance h of the sensor probe 31 relative to the measured point in the plane XOY is output; according to the real lifting distance h of the sensor probe 31 relative to the measured point in the plane XOY, the rotation radius r of the sensor probe 31 and the equally spaced angle θ between each measured point, the coordinates of the measured point in the measurement coordinate system are determined, as follows:

[0096]

[0097] Among them, x i and i are respectively the X-axis and Y-axis coordinates of the i-th measured point in the measuring coordinate system, i=1, 2, ..., I, I is the total number of measured points on the cross section of the inner arc surface of the gear sleeve part 4 in the measuring coordinate system, I=360 / θ.

[0098] The measured point refers to the three-dimensional coordinates (x i ,y i , z i ), where i is the number of the discrete point; z i The coordinates are determined by the end flange position of the motion control mechanism 1 and the geometric dimensions of the cantilever fixture 2 in the Z-axis direction. The end flange position changes with the movement of the motion control mechanism 1 and can be read directly. The geometric dimensions are fixed lengths and are obtained through measurement.

[0099] Step 4: Roughly measure and obtain the axis inclination angle information of the gear sleeve part 4.

[0100] The gear sleeve part 4 is roughly measured using the eddy current displacement sensor 3, and the axis inclination angle information of the gear sleeve part 4 is obtained according to the coordinates of the measured point in the measurement coordinate system, thereby obtaining the position and posture information of the gear sleeve part 4 in the rough measurement stage, as follows:

[0101] 1) In the rough measurement stage of the gear sleeve part 4, the sensor probe 31 rotates one circle around the rotation axis of the gear sleeve part 4, and the rotation section of the gear sleeve part 4 is parallel to the measurement coordinate system XOY. Generally, the gear sleeve part 4 is in an inclined state, and the rotation section of the gear sleeve part 4 intersects with the inner cylindrical surface of the gear sleeve part 4 to form an elliptical contour.

[0102] Perform ellipse fitting on a measured point on the cross section of the ellipse profile to obtain the coefficients of the ellipse profile (A γ , B γ , C γ , D γ , E γ , F γ ), thereby determining the ellipse; in addition to the algebraic equation, the ellipse can also be expressed by the coordinates of the center (x Ci ,y Ci ), the major semi-axis r of the ellipse a , short semi-axis r b The five geometric parameters, , the angle β between the major axis and the X axis, are uniquely determined. The coefficients of the algebraic equation can be converted into the required geometric parameters according to the following formula:

[0103]

[0104] Specifically, the coefficients of the algebraic equation of the ellipse (A) can be obtained by minimizing the following objective function J by using the direct least squares method to fit the ellipse algebraically. γ , B γ , C γ , D γ , E γ , Fγ ):

[0105]

[0106] Among them, A γ , B γ , C γ , D γ 、E γ and F γ are the first, second, third, fourth, and fifth coefficients of the algebraic equation of the ellipse.

[0107] 2) If Figure 8 As shown, the upper inner arc surface of the gear sleeve part 4 is subjected to rotational scanning, and the angle between the section where the contour ellipse of the gear sleeve part 4 is located and the perfect circular section passing through the center of the ellipse contour is obtained according to the curvature radius R of the inner arc surface of the gear sleeve part 4 and the geometric parameters of the ellipse contour According to the three perpendicular line theorem, we can get:

[0108]

[0109] Wherein, R is the curvature radius of the inner arc surface feature to be measured, which can be measured by an inner diameter gauge.

[0110] According to the angle Thus, the axis inclination angle information of the gear sleeve part 4 is obtained; at this time, only the inclination degree of the gear sleeve part 4 can be obtained, but it cannot be adjusted.

[0111] 3) According to the axis inclination angle information of the gear sleeve part 4 and the minor axis direction vector of the elliptical contour Determine the direction vector of the axis direction of the gear sleeve part 4 and the coordinates C of the center of the ellipse contour on the axis c =(x Ci ,y Ci , z Ci ), s1, s2 and s3 are the projections of the axial direction of the gear sleeve part 4 in the X, Y and Z axis directions of the measurement coordinate system, respectively. Ci ,y Ci and z Ci are the center C of the ellipse contour c In the X, Y and Z axis coordinates of the measurement coordinate system, the rotation axis of the eddy current displacement sensor 3 is parallel to the Z axis of the measurement coordinate system, and the unit vector of the rotation axis of the eddy current displacement sensor 3 is The minor axis direction vector of the ellipse outline The geometric parameters of the ellipse are used to obtain and finally determine the position and posture information of the axis of the gear sleeve part 4 in the rough measurement stage.

[0112] When determining the position information of the axis of the gear sleeve part 4 in the rough measurement stage, the direction vector of the axis direction of the gear sleeve part 4 can be set as The rotation axis is parallel to the Z axis of the measurement coordinate system, and the unit vector of the rotation axis is Inclination angle of gear sleeve part 4 It can be expressed in the form of vector inner product:

[0113]

[0114] The coordinates of the two endpoints A and E on the minor axis of the ellipse are (x Ci -r b sinβ,y Ci +r b cosβ,z Ci ) and (x Ci +r b sinβ,y Ci -r b cosβ,z Ci ), where z Ci = z of the sensor probe 31 at the current rotation time i Coordinates, direction vector of the minor axis It is expressed as (sinβ, -cosβ, 0). Any straight line passing through the center of the circle on the perfect circular cross section of the gear sleeve part 4 is perpendicular to the axis of the gear sleeve part 4. Therefore, We can get:

[0115] s1sinβ-s2cosβ=0, and finally the direction vector of the axis can be obtained as follows:

[0116]

[0117] At this time, we get the direction vector of the straight line and a point on the straight line, the center of the circle (x Ci ,y Ci ,z Ci ) coordinates, the position and posture information of the part axis obtained during the roughing stage can be determined.

[0118] The rough measurement method is used to measure the axis position of the gear sleeve part 4 in 5 different postures. The measurement results are as follows:

[0119] Table 1 Measurement results of ellipse parameters of the upper inner arc surface

[0120] Group <![CDATA[r a / mm]]> <![CDATA[r b / mm]]> β / ° x / mm y / mm z / mm 1 90.501 90.502 28.490 350.234 -1.919 350 2 90.523 90.494 -62.669 348.807 -0.0400 350 3 90.625 90.495 18.713 348.925 1.477 350 4 90.602 90.503 59.761 348.835 -1.654 350 5 90.541 90.496 29.545 350.128 -1.052 350

[0121] Table 2 Axis position information of gear sleeve parts obtained by rough measurement

[0122]

[0123] Step 5: Adjust the relative position between the sensor probe 31 and the gear sleeve part 4 to be measured.

[0124] According to the posture information of the gear sleeve part 4 in the rough measurement stage and the target assembly posture, the posture adjustment equipment is used to roughly adjust the relative posture between the rotation axis of the eddy current displacement sensor 3 and the axis of the gear sleeve part 4, so that the posture of the gear sleeve part 4 is adjusted to be close to the target assembly posture.

[0125] After the rough measurement phase of the gear sleeve part 4 is completed, the measured posture information can be converted into motion data of the posture adjustment device, and the posture adjustment device drives the gear sleeve part 4 to make corresponding adjustments so that it gradually approaches the assembly posture. Due to the positioning error of the posture adjustment device movement, a second measurement is required to verify the posture of the gear sleeve part 4 after the posture adjustment.

[0126] After the initial adjustment, the gear sleeve part 4 is close to the assembly position, and the inclination angle of its axis is very small. For example, when the angle between the rotation axis of the eddy current displacement sensor 3 and the axis of the gear sleeve part 4 is When measuring the inner arc surface with a curvature radius of 90.5mm, it can be found that the difference between the major axis and the minor axis of the elliptical trajectory is only 0.007mm, that is, the difference between the major axis and the minor axis of the elliptical contour is only 0.04‰ of the minor axis length. At this time, due to the limitation of the single ellipse parameter fitting on the solution of the axis inclination angle of the gear sleeve part 4, the credibility of the rough measurement method for solving the axis position of the gear sleeve part 4 is greatly reduced, and it is more susceptible to the fitting error of the ellipse deflection angle β. Therefore, the rough measurement method cannot be verified and it is necessary to enter the next step of fine measurement.

[0127] Step 6: Accurately measure and obtain the center of the cross-section contour of the gear sleeve part 4.

[0128] like Fig. 9 As shown, the eddy current displacement sensor 3 is used to precisely measure the roughly adjusted gear sleeve part 4, and the inner arc surfaces at the upper and lower positions of the gear sleeve part 4 are rotated to measure the center coordinates of the elliptical cross-section profiles of the two inner arc surfaces of the gear sleeve part 4 in the measurement coordinate system, so as to complete the precise measurement of the axis position, as follows:

[0129] The sensor probe 31 of the eddy current displacement sensor 3 is moved along the vertical rotation axis, and the elliptical cross-sectional contours whose inner arc surfaces at the upper and lower positions of the gear sleeve part 4 are parallel to the plane XOY are selected. Each elliptical cross-sectional contour is fitted by elliptical least squares to obtain the center position of each elliptical cross-sectional contour. The center of each elliptical cross-sectional contour is added with the Z coordinate of the cross section where it is located to obtain the spatial coordinates C1=(x 11 ,y 11 ,z 11 ) and C2=(x 22 ,y 22 ,z22 ), where x 11 ,y 11 and z 11 are the X, Y, and Z axis coordinates of the center of the first elliptical cross-section profile in the measurement coordinate system, respectively. 22 ,y 22 and z 22 are the X, Y and Z axis coordinates of the center of the second elliptical cross-section contour in the measurement coordinate system. According to the theory of spatial geometry, the straight line L formed by connecting the spatial coordinates of the centers of the two elliptical cross-section contours is C Theoretically, it should coincide with the axis of the gear sleeve part 4.

[0130] The results of measuring the inner arc surface of the gear sleeve part 4 at the upper and lower positions using the precision measurement method are shown in the following table, and the spatial coordinates of the centers of the two ellipses can be obtained.

[0131] Table 3 Ellipse center measurement results in the precision measurement stage

[0132]

[0133] Step 7: Calculate the axis position parameters of the gear sleeve part 4.

[0134] The spatial position of the axis of the gear sleeve part 4 is calculated according to the center coordinates of the elliptical cross-section contour of the two inner arc surfaces of the gear sleeve part 4, and finally the spatial position of the axis of the gear sleeve part 4 is adjusted to the target assembly position to complete the assembly position adjustment of the gear sleeve part 4.

[0135] The axis of the gear sleeve part 4 belongs to the space straight line, and its direction and direction vector Similarly, according to the center coordinates of the elliptical cross-section contours of the two inner arc surfaces of the gear sleeve part 4, the spatial equation of the axis of the gear sleeve part 4 is determined as follows:

[0136]

[0137] p=s1 / s3

[0138] q=s2 / s3

[0139] Among them, x, y and z are the X, Y and Z axis coordinates of a point on the axis of the gear sleeve part 4 in the measurement coordinate system; p and q are the first and second direction vector parameters; x0 and y0 are the X and Y axis coordinates of the intersection point C0 of the axis of the gear sleeve part 4 and the XOY plane of the measurement coordinate system, z0 = 0; s1, s2 and s3 are the direction vectors of the axis direction of the gear sleeve part 4 Projection in the X, Y and Z directions of the measurement coordinate system;

[0140] For the axis measurement requirements of the inner cylindrical surface features, it is necessary to determine the direction of the axis. The movement of the cylinder up and down along the axis and the rotation around its own axis will not affect the measurement result of the axis. Therefore, the axis equation is simplified and the point through which the axis passes is set on the XOY plane of the measurement coordinate system, that is, z0=0. Assuming p=s1 / s3 and q=s2 / s3, a simplified expression of the axis space equation can be obtained.

[0141] The coordinates of the center of the elliptical cross-section contour of the two inner arc surfaces of the gear sleeve part 4 are input into the spatial equation of the gear sleeve part 4 for processing to obtain the coordinates of the intersection point C0 of the axis of the gear sleeve part 4 and the XOY plane of the measurement coordinate system and the direction vector of the axis direction of the gear sleeve part 4 The details are as follows:

[0142]

[0143] Among them, x 11 ,y 11 and z 11 are the X, Y and Z axis coordinates of the center C1 of the first elliptical cross-section profile in the measurement coordinate system, respectively. 22 ,y 22 and z 22 are respectively the X, Y and Z axis coordinates of the center C2 of the second elliptical cross-section profile in the measurement coordinate system;

[0144] The coordinates of the intersection point C0 of the axis of the gear sleeve part 4 and the XOY plane of the measurement coordinate system and the direction vector of the axis direction of the gear sleeve part 4 are calculated. As the posture parameter of the axis of the gear sleeve part 4, the spatial posture of the axis of the gear sleeve part 4 is further determined.

[0145] The precise axis position information of the gear sleeve part 4 is obtained by accurately measuring the coordinates of the center of the ellipse, as shown in Table 4 below.

[0146] Table 4 Axis position information of gear sleeve parts in the precision measurement stage

[0147]

[0148] In the method for measuring the axis position of the gear sleeve part 4 in the above embodiment, the present invention corrects the measurement error of the inner arc surface feature measured by eddy current to obtain an ideal detection effect, and the detection error is controlled within 0.017mm.

[0149] The above description and embodiments are only preferred examples of the present invention and do not constitute any limitation to the present invention. It is obvious that for professionals in this field, after understanding the content and design principles of the present invention, they may make various modifications and changes in form and details based on the principles and structures of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A method for adjusting the assembly posture of helicopter gear sleeve parts based on eddy current ranging, characterized in that: include: Step 1) constructing a gear sleeve part position and posture measurement system including an eddy current displacement sensor (3) and establishing a measurement coordinate system; Step 2) in the measurement coordinate system, when the eddy current displacement sensor (3) of the gear sleeve part posture measurement system performs measurement error correction on the inner arc surface feature of the helicopter gear sleeve part (4), thereby establishing an eddy current correction model; Step 3) using the eddy current displacement sensor (3) of the gear sleeve part posture measurement system to perform a rotational scanning measurement on the measured point on the gear sleeve part (4), thereby obtaining the measured distance and offset of the measured point, inputting the measured distance and offset of the measured point into the eddy current correction model for processing to obtain the actual lift-off distance of the measured point, and determining the coordinates of the measured point in the measurement coordinate system according to the rotation radius of the eddy current displacement sensor (3), the equally spaced angles between the measured points on the gear sleeve part (4), and the actual lift-off distance of the measured point; Step 4) using the eddy current displacement sensor (3) to perform a rough measurement on the gear sleeve part (4), obtaining the axis inclination angle information of the gear sleeve part (4) according to the coordinates of the measured point in the measurement coordinate system, and then obtaining the position and posture information of the gear sleeve part (4) in the rough measurement stage; Step 5) Based on the posture information of the gear sleeve part (4) in the rough measurement stage and the target assembly posture, a posture adjustment device is used to roughly adjust the relative posture between the rotation axis of the eddy current displacement sensor (3) and the axis of the gear sleeve part (4), so that the posture of the gear sleeve part (4) is adjusted to be close to the target assembly posture; Step 6) using an eddy current displacement sensor (3) to precisely measure the roughly adjusted gear sleeve part (4), thereby obtaining the center coordinates of the elliptical cross-section profiles of the two inner arc surfaces of the gear sleeve part (4) in the measurement coordinate system; Step 7) The spatial position of the axis of the gear sleeve part (4) is calculated based on the center coordinates of the elliptical cross-section contour of the two inner arc surfaces of the gear sleeve part (4), and finally the spatial position of the axis of the gear sleeve part (4) is adjusted to the target assembly position, thereby completing the assembly position adjustment of the gear sleeve part (4).

2. The method for adjusting the assembly posture of helicopter gear sleeve parts based on eddy current ranging according to claim 1 is characterized in that: In the step 1), the gear sleeve part posture measurement system also includes a motion control mechanism (1) and a cantilever fixture (2), the motion control mechanism (1) has at least 4 degrees of freedom, including 3 translational degrees of freedom in the spatial rectangular coordinate direction and a rotational degree of freedom around the vertical direction, the end flange of the motion control mechanism (1) is connected to the cantilever fixture (2), and a positioning pin hole is provided on the end flange; the cantilever fixture (2) includes a crossbeam (21) and a longitudinal beam (22), the end flange of the motion control mechanism (1) is connected to the upper surface of one end of the crossbeam (21), the radial direction of the end flange is parallel to the length direction of the crossbeam (21), the lower surface of the crossbeam (21) is provided with a slide groove along its own length direction, the top end of the longitudinal beam (22) is slidably installed in the slide groove of the crossbeam (21), and the longitudinal beam (22) is provided with a slide groove along its own length direction. ) moves along the slide groove; a reinforcing rib is provided on the longitudinal beam (22) to prevent bending deformation; a through hole for installing an eddy current displacement sensor (3) is opened at the bottom end of the longitudinal beam (22); the eddy current displacement sensor (3) comprises a sensor probe (31), a sensor connection cable (32) and a sensor fixing nut (33); the sensor probe (31) is installed in the through hole of the longitudinal beam (22) through the sensor fixing nut (33); the sensor probe (31) is connected to an external sensor processing device through the sensor connection cable (32); the orientation of the sensor probe (31) is parallel to the length direction of the cross beam (21); the straight-line distance between the central symmetric point of the positioning pin hole on the end flange and the head of the sensor probe (31) is used as the turning radius r of the eddy current displacement sensor (3); The measurement coordinate system of the gear sleeve part posture measurement system takes the center of the base bottom surface of the motion control mechanism (1) as the origin O, takes the measurement direction of the eddy current displacement sensor (3) along its axis after installation as the X-axis, and takes the vertical upward direction as the Z-axis to establish a right-handed rectangular coordinate system O-XYZ.

3. The method for adjusting the assembly posture of helicopter gear sleeve parts based on eddy current ranging according to claim 2 is characterized in that: The step 2) is as follows: Step 2.1) The eddy current displacement sensor (3) is driven to move into the gear sleeve part (4) by the motion control mechanism (1), and a plurality of measured points are provided at equal intervals on the inner surface of the gear sleeve part (4); the sensor probe (31) of the eddy current displacement sensor (3) is centered, and the sensor probe (31) is driven to move in steps along the X-axis and the Y-axis of the measurement coordinate system in the gear sleeve part (4) by the motion control mechanism (1), and the range of the eddy current displacement sensor (3) is determined, so that the eddy current displacement sensor (3) is located within the range when moving, and at the same time, the axis of the sensor probe (31) is coincident with the normal vector of the measured point currently being measured; Step 2.2) Use an eddy current displacement sensor (3) to measure the inner arc surface feature of the gear sleeve part (4), change the lift-off distance h and the offset δ of the sensor probe (31) relative to the measured point in the plane XOY, the lift-off distance is the actual distance of the surface of the sensor probe (31) relative to the measured point, at this time, the measurement distance H of the sensor probe (31) is not equal to the actual lift-off distance, calibrate the N kinds of offsets of the same inner arc surface feature at M kinds of lift-off distances, and obtain M×N kinds of measurement distances H (m, n) and sensor lift-off distances h (m, n) of the sensor probe (31), wherein m=1, 2, ..., M, and n=1, 2, ..., N; Step 2.3) For each offset, all M lift-off distances h and measured distances H under the current offset are fitted with a second-order polynomial, thereby obtaining a second-order polynomial fitting result of the offset. The second-order polynomial fitting result of the offset is h(m, n) = A ε (n)·H(m,n) 2 +B ε (n)·H(m,n)+C ε (n), obtain the first polynomial parameter A of the nth offset according to the second-order polynomial fitting result ε (n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n); Step 2.4) For each offset, the first polynomial parameter A of the current offset is ε (n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n) Perform a second-order polynomial fit to obtain the first polynomial parameter A ε (n), the second polynomial parameter B ε (n) and the third polynomial parameter C ε (n) The second-order polynomial fitting result, the first polynomial parameter A ε The second-order polynomial fitting result of (n) is A ε ′(n), the second polynomial parameter B ε The second-order polynomial fitting result of (n) is B ε ′(n), the third polynomial parameter C ε The second-order polynomial fitting result C of (n) ε ′(n), thereby obtaining the first intermediate correction parameter A ε0 , the second intermediate correction parameter A ε1 , the third intermediate correction parameter A ε2 , the fourth intermediate correction parameter B ε0 , the fifth intermediate correction parameter B ε1 , the sixth intermediate correction parameter B ε2 , the seventh intermediate correction parameter C ε0 , the eighth intermediate correction parameter C ε1 and the ninth intermediate correction parameter C ε2 , where T(n) is the offset distance of the nth offset; Step 2.5) obtains the measurement distance H of the sensor probe (31), and at the same time establishes an eddy current correction model based on the offset δ of the sensor probe (31) relative to the measured point in the plane XOY and the nine intermediate correction parameters δ in step 2.4).

4. The method for adjusting the assembly posture of helicopter gear sleeve parts based on eddy current ranging according to claim 3 is characterized in that: In the step 2.5), the eddy current correction model is as follows: h=A ε ′(n)·H 2 +B ε ′(n)·H+C ε ′(n) A ε ′(n)=A ε0 ·d 2 +A ε1 ·d+A ε2 B ε ′(n)=B ε0 ·d 2 +B ε1 ·d+B ε2 C ε ′(n)=C ε0 ·d 2 +C ε1 ·d+C ε2 Wherein, h is the actual lifting distance of the sensor probe (31) relative to the measured point in the plane XOY.

5. The method for adjusting the assembly posture of helicopter gear sleeve parts based on eddy current ranging according to claim 2 is characterized in that: The step 3) is specifically as follows: in the measurement of the axis position of the gear sleeve part (4), the motion control mechanism (1) drives the sensor probe (31) to perform a rotational scan, and synchronously obtains the measurement data of the sensor probe (31), including the measurement distance H of the sensor probe (31) and the offset δ relative to the measured point in the plane XOY, and inputs the measurement data of the sensor probe (31) into the eddy current correction model for processing. After the eddy current correction model is processed, the actual lifting distance h of the sensor probe (31) relative to the measured point in the plane XOY is output; according to the actual lifting distance h of the sensor probe (31) relative to the measured point in the plane XOY, the rotation radius r of the sensor probe (31) and the equally spaced angle θ between each measured point, the coordinates of the measured point in the measurement coordinate system are determined, as follows: Among them, x i and i are respectively the X-axis and Y-axis coordinates of the i-th measured point in the measuring coordinate system, i=1, 2, ..., I, I is the total number of measured points on the cross section of the inner arc surface of the gear sleeve part (4) in the measuring coordinate system, I=360 / θ.

6. The method for adjusting the assembly posture of helicopter gear sleeve parts based on eddy current ranging according to claim 2 is characterized in that: The step 4) is as follows: Step 4.1) During the rough measurement stage of the gear sleeve part (4), the sensor probe (31) rotates one circle around the rotation axis of the gear sleeve part (4), the rotation section of the gear sleeve part (4) is parallel to the measurement coordinate system XOY, the gear sleeve part (4) is in an inclined state, and the rotation section of the gear sleeve part (4) intersects with the inner cylindrical surface of the gear sleeve part (4) to form an elliptical contour; Step 4.2) Obtain the angle between the section where the contour ellipse of the gear sleeve part (4) is located and the perfect circular section passing through the center of the ellipse contour according to the curvature radius R of the inner arc surface of the gear sleeve part (4) and the geometric parameters of the ellipse contour. Thus, the axis inclination angle information of the gear sleeve part (4) is obtained; Step 4.3) According to the axis inclination angle information of the gear sleeve part (4) and the minor axis direction vector of the elliptical contour Determine the direction vector of the axis direction of the gear sleeve part (4) and the coordinates C of the center of the ellipse contour on the axis c =(x Ci ,y Ci , z Ci ), s1, s2 and s3 are projections of the axial direction of the gear sleeve part (4) in the X, Y and Z axis directions of the measurement coordinate system, respectively. Ci ,y Ci and z Ci are the center C of the ellipse contour c In the measurement coordinate system, the X, Y and Z axis coordinates, the rotation axis of the eddy current displacement sensor (3) is parallel to the Z axis of the measurement coordinate system, and finally the position information of the axis of the gear sleeve part (4) in the rough measurement stage is determined.

7. The method for adjusting the assembly posture of helicopter gear sleeve parts based on eddy current ranging according to claim 2 is characterized in that: The step 6) is specifically as follows: using the sensor probe (31) of the eddy current displacement sensor (3) to move along the vertical rotation axis, selecting the elliptical cross-sectional profiles of the inner arc surfaces at the upper and lower positions of the gear sleeve part (4) parallel to the plane XOY, performing elliptical least squares fitting on each elliptical cross-sectional profile to obtain the center position of each elliptical cross-sectional profile, adding the Z coordinate of the cross section where the center of each elliptical cross-sectional profile is located, and obtaining the spatial coordinates C1=(x 11 ,y 11 , z 11 ) and C2=(x 22 ,y 22 , z 22 ), where x 11 ,y 11 and z 11 are the X, Y, and Z axis coordinates of the center of the first elliptical cross-section profile in the measurement coordinate system, respectively. 22 ,y 22 and z 22 They are respectively the X, Y, and Z axis coordinates of the center point of the second elliptical cross-section profile in the measurement coordinate system.

8. The method for adjusting the assembly posture of helicopter gear sleeve parts based on eddy current ranging according to claim 2 is characterized in that: The step 7) is specifically to determine the spatial equation of the axis of the gear sleeve part (4) according to the center coordinates of the elliptical cross-section contour of the two inner arc surfaces of the gear sleeve part (4) as follows: p=s1 / s3 q=s2 / s3 Wherein, x, y and z are respectively the X, Y and Z axis coordinates of a point on the axis of the gear sleeve part (4) in the measurement coordinate system; p and q are respectively the first and second direction vector parameters; x0 and y0 are respectively the X and Y axis coordinates of the intersection point C0 of the axis of the gear sleeve part (4) and the XOY plane of the measurement coordinate system; s1, s2 and s3 are respectively the direction vectors of the axis direction of the gear sleeve part (4) Projection in the X, Y and Z directions of the measurement coordinate system; The coordinates of the center points of the elliptical cross-section contours of the two inner arc surfaces of the gear sleeve part (4) are input into the spatial equation of the gear sleeve part (4) for processing to obtain the coordinates of the intersection point C0 of the axis of the gear sleeve part (4) and the XOY plane of the measurement coordinate system and the direction vector of the axis direction of the gear sleeve part (4). The details are as follows: Among them, x 11 ,y 11 and z 11 are the X, Y and Z axis coordinates of the center C1 of the first elliptical cross-section profile in the measurement coordinate system, respectively. 22 ,y 22 and z 22 are respectively the X, Y and Z axis coordinates of the center C2 of the second elliptical cross-section profile in the measurement coordinate system; The coordinates of the intersection point C0 of the axis of the gear sleeve part (4) and the XOY plane of the measurement coordinate system and the direction vector of the axis direction of the gear sleeve part (4) are As the position and posture parameters of the axis of the gear sleeve part (4), the spatial position and posture of the axis of the gear sleeve part (4) is further determined.

9. An electronic device, characterized in that: include: A memory and a processor coupled to each other, wherein the memory stores program data, and the processor calls the program data to execute the method according to any one of claims 1 to 8.

10. A computer-readable storage medium having program data stored thereon, characterized in that: When the program data is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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